Since I will be listing my full database on /bots, and I want to use id instead of _id (discord uses id for everything, so I'm accustomed with id and not _id)
I don't even want to save id as _id in the database. So any idea what to do?
This is not possible!
MongoDB automatically creates an _id for every document that gets inserted into a database.
This is there in order to give you a one-to-one value that you will be able to use to identify each document.
The id also contains a timestamp to when you inserted the document which then can be used to optimize queries using indexes.
This is also a best practice to send the _id to the user (even if it's mapped to an id field) to then be able to query more efficiently and also to not expose their Discord Id to everyone.
Hope I could answer your question.
You could read more about it here:
https://docs.mongodb.com/manual/core/document/#the-id-field
How to remove _id in MongoDB and replace with another field as a Primary Key?
The save() method seems to replace an entire document/record in my database. If I know the primary key of a document in my database, what is the best way in Grails for me to update a single field on that document without first querying the database using get()?
For instance, I don't like the following code because it executes two queries when all I want to do is to update myField.
def key = "foo"
def doc = MyDomain.get(key) // This is the query I want to eliminate
doc.myField = "bar"
doc.save()
In situations where I know the primary key, I want to simply update a single field, similarly to how Ruby on Rails leverages the ActionModel.update_attribute() method.
Even though my specific database is MongoDB, I think the question is applicable to any database, SQL or NoSQL. If the database supports the ability to update just a single field on one record via one query, using Grails can I avoid the extra get() query to retrieve a full record from the database?
I'm trying to build routes in my Meteor app. Routing works perfectly fine but getting information from db with route path just doesn't work. I create my page specific routes with this:
FlowRouter.route('/level/:id'...
This route takes me to related template without a problem. Then I want to get some data from database that belong to that page. In my template helpers I get my page's id with this:
var id = FlowRouter.getParam('id');
This gets the ObjectID() but in string format. So I try to find that ObjectID() document in the collection with this:
Levels.findOne({_id: id});
But of course documents doesn't have ObjectIDs in string format (otherwise we wouldn't call it "object"id). Hence, it brings an undefined error. I don't want to deal with creating my own _ids so is there anything I can do about this?
PS: Mongo used to create _ids with plain text. Someting like I would get with _id._str now but all of a sudden, it generates ObjectID(). I don't know why, any ideas?
MongoDB used ObjectIds as _ids by default and Meteor explicitly sets GUID strings by default.
Perhaps you inserted using a meteor shell session in the past and now used a mongo shell/GUI or a meteor mongo prompt to do so, which resulted in ObjectIds being created.
If this happens in a development environment, you could generate the data again.
Otherwise, you could try to generate new _ids for your data using Meteor.uuid().
If you want to use ObjectId as the default for a certain collection, you can specify the idGeneration option to its constructor as 'MONGO'.
If you have the string content of an ObjectId and want to convert it, you can issue
let _id = new Mongo.ObjectID(my23HexCharString);
I am retrieving records from Mongo using Meteor. I use the {{_id}} placeholder in my meteor template to use the _id field of the record, but it adds this into my template....
ObjectID("54f27a1adfe0c11c824e04e9")
... and I would like just to have...
54f27a1adfe0c11c824e04e9
How do I do this?
Just add a global helper:
Template.registerHelper('formatId', function(data) {
return (data && data._str) || data;
});
You can also do it like this with ES6 syntax :
Template.registerHelper('formatId', (id) => (id && id._str) || id);
And use it in any template like this:
{{formatId _id}}
This will work for both mongo-style ObjectIds and meteor-style random strings.
Since your documents are using the MongoDB ID format rather than the default Meteor ID format (simply a randomly generated string), you will need to use the MongoDB ObjectId.toString() function described here. But unfortunately, this simply results in your ObjectID being printed out as a string like ObjectID("54f27a1adfe0c11c824e04e9").
I would recommend creating a document ID template helper that cleans your document IDs before including them in the template. Since this issue is most likely related to all of your documents in all of your collections, I would further suggest creating a global template helper. This can be done like so:
Template.registerHelper('cleanDocumentID', function(objectID) {
var objectIdString = objectID.toString();
var cleanedString = objectIDString.slice(objectIDString.indexOf('"') + 1, -2);
return cleanedString;
});
This template helper slices out just the actual object ID string from the string provided by the ObjectId.toString() function. You can use this template helper in your templates like so:
{{cleanDocumentID _id}}
I know that this is a lot messier than simply using the document ID in the template like {{_id}}, but it is necessary due to the fact that your documents have the MongoDB ObjectID-type document ID rather than the simple randomly generated string as used by Meteor by default.
If you would like to learn more about how to set your MongoDB collections to use randomly generated strings for document IDs and avoid this mess, check out this.
In Blaze templates, just add this {{_id.valueOf}}, and you will have a string value of the actual Object Id.
mongo is capable of storing many types including uuids and custom ones. the field is usually a self-describing object, comprised of the type and the id.
your record is using the default mongo format evidenced by the "ObjectId" prefix.
try ObjectId("507f191e810c19729de860ea").str
So this is Day 3 of learning Mongo Db. I'm coming from the MySql universe...
A lot of times when I need to write a query for a MySql table I'm unfamiliar with, I would use the "desc" command - basically telling me what fields I should include in my query.
How would I do that for a Mongo db? I know, I know...I'm searching for a schema in a schema-less database. =) But how else would users know what fields to use in their queries?
Am I going at this the wrong way? Obviously I'm trying to use a MySql way of doing things in a Mongo db. What's the Mongo way?
Type the below query in editor / mongoshell
var col_list= db.emp.findOne();
for (var col in col_list) { print (col) ; }
output will give you name of columns in collection :
_id
name
salary
There is no good answer here. Because there is no schema, you can't 'describe' the collection. In many (most?) MongoDb applications, however, the schema is defined by the structure of the object hierarchy used in the writing application (java or c# or whatever), so you may be able to reflect over the object library to get that information. Otherwise there is a bit of trial and error.
This is my day 30 or something like that of playing around with MongoDB. Unfortunately, we have switched back to MySQL after working with MongoDB because of my company's current infrastructure issues. But having implemented the same model on both MongoDB and MySQL, I can clearly see the difference now.
Of course, there is a schema involved when dealing with schema-less databases like MongoDB, but the schema is dictated by the application, not the database. The database will shove in whatever it is given. As long as you know that admins are not secretly logging into Mongo and making changes, and all access to the database is controller through some wrapper, the only place you should look at for the schema is your model classes. For instance, in our Rails application, these are two of the models we have in Mongo,
class Consumer
include MongoMapper::Document
key :name, String
key :phone_number, String
one :address
end
class Address
include MongoMapper::EmbeddedDocument
key :street, String
key :city, String
key :state, String
key :zip, String
key :state, String
key :country, String
end
Now after switching to MySQL, our classes look like this,
class Consumer < ActiveRecord::Base
has_one :address
end
class Address < ActiveRecord::Base
belongs_to :consumer
end
Don't get fooled by the brevity of the classes. In the latter version with MySQL, the fields are being pulled from the database directly. In the former example, the fields are right there in front of our eyes.
With MongoDB, if we had to change a particular model, we simply add, remove, or modify the fields in the class itself and it works right off the bat. We don't have to worry about keeping the database tables/columns in-sync with the class structure. So if you're looking for the schema in MongoDB, look towards your application for answers and not the database.
Essentially I am saying the exactly same thing as #Chris Shain :)
While factually correct, you're all making this too complex. I think the OP just wants to know what his/her data looks like. If that's the case, you can just
db.collectionName.findOne()
This will show one document (aka. record) in the database in a pretty format.
I had this need too, Cavachon. So I created an open source tool called Variety which does exactly this: link
Hopefully you'll find it to be useful. Let me know if you have questions, or any issues using it.
Good luck!
AFAIK, there isn't a way and it is logical for it to be so.
MongoDB being schema-less allows a single collection to have a documents with different fields. So there can't really be a description of a collection, like the description of a table in the relational databases.
Though this is the case, most applications do maintain a schema for their collections and as said by Chris this is enforced by your application.
As such you wouldn't have to worry about first fetching the available keys to make a query. You can just ask MongoDB for any set of keys (i.e the projection part of the query) or query on any set of keys. In both cases if the keys specified exist on a document they are used, otherwise they aren't. You will not get any error.
For instance (On the mongo shell) :
If this is a sample document in your people collection and all documents follow the same schema:
{
name : "My Name"
place : "My Place"
city : "My City"
}
The following are perfectly valid queries :
These two will return the above document :
db.people.find({name : "My Name"})
db.people.find({name : "My Name"}, {name : 1, place :1})
This will not return anything, but will not raise an error either :
db.people.find({first_name : "My Name"})
This will match the above document, but you will have only the default "_id" property on the returned document.
db.people.find({name : "My Name"}, {first_name : 1, location :1})
print('\n--->', Object.getOwnPropertyNames(db.users.findOne())
.toString()
.replace(/,/g, '\n---> ') + '\n');
---> _id
---> firstName
---> lastName
---> email
---> password
---> terms
---> confirmed
---> userAgent
---> createdAt
This is an incomplete solution because it doesn't give you the exact types, but useful for a quick view.
const doc = db.collectionName.findOne();
for (x in doc) {
print(`${x}: ${typeof doc[x]}`)
};
If you're OK with running a Map / Reduce, you can gather all of the possible document fields.
Start with this post.
The only problem here is that you're running a Map / Reduce on which can be resource intensive. Instead, as others have suggested, you'll want to look at the code that writes the actual data.
Just because the database doesn't have a schema doesn't mean that there is no schema. Generally speaking the schema information will be in the code.
I wrote a small mongo shell script that may help you.
https://gist.github.com/hkasera/9386709
Let me know if it helps.
You can use a UI tool mongo compass for mongoDb. This shows all the fields in that collection and also shows the variation of data in it.
If you are using NodeJS and want to get the all the field names using the API request, this code works for me-
let arrayResult = [];
db.findOne().exec(function (err, docs)){
if(err)
//show error
const JSONobj = JSON.parse(JSON.stringify(docs));
for(let key in JSONobj) {
arrayResult.push(key);
}
return callback(null, arrayResult);
}
The arrayResult will give you entire field/ column names
Output-
[
"_id",
"emp_id",
"emp_type",
"emp_status",
"emp_payment"
]
Hope this works for you!
Consider you have collection called people and you want to find the fields and it's data-types. you can use below query
function printSchema(obj) {
for (var key in obj) {
print( key, typeof obj[key]) ;
}
};
var obj = db.people.findOne();
printSchema(obj)
The result of this query will be like below,
you can use Object.keys like in JavaScript
Object.keys(db.movies.findOne())